Liquefied gas extractor



R E P w Q a H LIQUEFIED GAS MTRAG'I'OR Filed Aug. 18; 1945 mmvma Ham-21. CT (wanna Patented May 4,1948

UNITED STATES PATENT OFFICE momma GAS EXTRACTOR Howell C. Cooper, Sewickley, Pa.

Application August 18, 1945, Serial No. 611,278 3 Claims. (Cl. cz-m) 'I'his'invention relates to extraction of liquefied gas from a closed container. and more particularly contemplates extraction of liquefled natural gas from a large container wherein the liquid has been stored, at a temperature in the order of a 250 F. and at atmospheric pressure or only slightly thereabove as has become a practice for standby purposes in the natural gas industry.

The invention contemplates storage in a tank or bottle or plurality thereof, in the order of 40 feet or more in height, buried or largely disposed in the ground so that a bottom drainage opening would be impractical.

Objects of the invention are to provide extraction of such liquid with the least heat loss thereinto and consequent gasiiication thereof, andwith a minimum of power, by inexpensive means adapted to serve a large number of containers; all as will appear hereinafter.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing which is a more or less diagrammatic and conventionalized view illustrative of an embodiment of the invention.

With reference now to the drawing, I is the container for liquefied gas, which may be provided with suitable insulation and buried in the ground, and may be one of many there located. It has a single opening only, located at the top, through which it may be charged with liquefied gas by way of a pipe 2 having a suitable vent 3. i is a tank into which it is desired the liquid contents of the container I be transferred, the tank t being in practice at a higher elevation than the container I, so that its liquid may be withdrawn as desired by gravity through the outlet pipe I.

According to this invention, the container I is provided with pump means of the air-lift type, comprising outer and inner tubes 5 and Ii, respectively, the tubes extending downwardly into the container but terminating with open ends short of the bottom thereof, the inner tube Ii being perforated adjacent its lower ends, as indicated at 6 and the outer tube 5 being closed at its upper end with the exception of the tube ii'which extends therethrough. As will be appreciated by one familiar with the art, the arrangement is such that when the gas is pumped into the upper end of the tube 6, it will produce bubbles of vapor at the lower end, which bubbles will rise in the annular space between the two tubes entraining the liquid, the column of mixed gas and liquid rising and finding an exit from the container by way of the pipe I.

According to this invention, the gas employed in the pump is the vapor of the liquid contents 1 pump tube 6 with a connection III providing I communication with the space within the container I above the liquid therein. The connection I0 is preferably valved as at I ll or otherwise somewhat restricted so that the pressure applied to the tube 8 will be sumciently greater than that above the liquid so that the pump will operate as described.

The liquid outlet pipe I leads into a separator II from the bottom of which liquid gas flows to the tank 4 by way of the pipe I2, the vapor emerging from the top of the separator by way of the pipe line I3 leading to the compressor 8. The top of the tank 4 may be vented to the line It as indicated at I4. The line 9, after the compressor 8, may be vented as at I5, valved as indicated so that the system may be relieved of excess vapors; in practice, the connection I5 leading to the gas distributing system to be served by the regasified liquid, and a secondcompressor, not illustrated, being employed if necessary to overcome the pressure of such distributing system.

In order to minimize regasiflcation within the system, a. heat exchanger I6 is provided, arranged ln the lines 9 and I3 as indicated, to cool the vapor discharged by the compressor and not vented at I5, by the refrigeration effectof the vapor leaving the separator II and received from the tank i by way of the connection I4.

Where the system is to servea number of containers I, suitable valved connections I! and I8 are located in the lines I and 9, respectively, which latter are valved as at I9 and 20, so as to provide optional application of the system to selected containers to be emptied-all as will be evident to one familiar with the art.

I-claim:

1. The method of extracting liquefied gas from a closed container comprising coincidently entraining portions of the liquid contents of said container in an outfiowing stream of vapor of said liquid, separating the liquid and vapor portions of said stream, and returning a sufilclent portion of the separated vapor to said container to provide said stream and to displace the liquid entra ned thereby- 2. The method of extracting liquefied gas drum a closed container comprisingcoincidently entraining' within the container, liquid portions of the container'contents in an outflowing stream 0! the vapor thereof, separating. outside the container, the liquid and vapor contents of the combined stream, compressing said separated vapor contents to provide circulation 01' said stream, vapor contents of said stream and the com pressed vapor, and returning suflicient oi said compressed vapor to said container to provide said entrainment stream and to displace the liquid entrained thereby,

3. The method of extracting liquefied gas from a closed container comprising coincidently entraining, within the container, liquid portions of the container contents in an outflowing stream of the vapor thereof, separating, outside the conexchanging heatbetween separated,

tainer, the liquid and vapor contents of the combined stream, compressing said separated vapor contents to provide circulation of said stream,

REFERENCES orrnn The iollowingreferences are of record in the file or this patent:

UNITED STATES PATENTS Name Date Gunning Nov. 22, 1864 Number 

